PHP2Shell: No login, no app code, no warning. What next?

If you run PHP anywhere in your environment, patch to PHP 8.5.12, 8.4.27, 8.3.36 or 8.2.35 now. Two critical flaws disclosed last week, CVE-2026-109618 and CVE-2026-109619 (nicknamed "PHP2Shell"), let an unauthenticated attacker run code on a server with nothing more than a crafted web request. Both carry a CVSS v4.0 score of 9.2, every earlier release is affected, and exploitation in the wild has been reported. The patch is the easy part. The hard part is finding every copy of PHP you own, because PHP rarely shows up where you expect it. This post covers what the flaws are, how far exploitation has gone, and how to get to full coverage fast. What happened Details leaked before the planned embargo, so the PHP security team moved fast and shipped fixes within about a day of announcing them. The two vulnerabilities Both bugs live in PHP core, not in any framework or plugin, so they reach anything that runs PHP to serve web requests. Affected server setups include PHP-FPM, mod_php, php-cgi, FrankenPHP and LiteSpeed. PHP rates mod_php as the highest risk. No login is needed: the attacker only has to reach a PHP endpoint over HTTP. Fixed versions: 8.5.12, 8.4.27, 8.3.36 and 8.2.35. Every earlier release is affected. PHP has also published minimal source backports for 7.4, 8.0 and 8.1, but there are no official releases for those branches. Treat a backport as a stopgap and plan the upgrade. Is it being exploited? Yes, though reliable public exploits are still scarce. watchTowr reports exploitation in its honeypot network as of October 21, and Tenable relays Cloudflare's CTO saying Cloudflare is seeing early attacks. Other telemetry, such as Patchstack's, shows mostly probing so far. Neither CVE is in CISA's KEV catalog yet, and no public indicators of compromise have been released. How hard the bug is to weaponize depends on the platform. VulnCheck reproduced both flaws and found: Code execution works on ARM64, and on x86 systems where address space layout randomization (ASLR) is turned off. Dozens of public proof-of-concepts exist, but very few work and none bypass ASLR on x86-64. Red Hat likewise rates RCE as hard in practice on default PHP-FPM deployments. Don't read that as permission to wait. Exploits mature quickly once a patch diff is public, and fake PoC repositories for headline CVEs often carry malware, so treat any you find with caution. Tanium's research on exploitability is in Why PHP2Shell is real(opens in a new tab). Most at risk: internet-facing …